1. Field of the Invention:
This invention relates to solid state imaging apparatus and more particularly to a solid state imaging apparatus photoelectrically converting an object image to an electric signal and to be used for an electronic still camera or video camera.
2. Related Art Statement:
In an electronic still camera or video camera, there is a characteristic that, in case an image is formed on the light receiving surface of a solid state imaging device and is converted to an electric signal, a moire will be likely to be caused by a spatial frequency. Therefore, usually, as shown in FIG. 8, a low pass filter (abbreviated as an LPF hereinafter) 23 formed of crystal plates to prevent such moire is arranged in the rear of an imaging optical system consisting of zoom lens groups 21 and 22 formed, for example, of two groups. Further, as required, an infrared ray cutting filter 24 for cutting infrared rays is also arranged.
In order that the above mentioned crystal LPF 23 may develop the optical high-frequency cut off effect sufficiently to prevent the moire, the crystal LPF 23 must be arranged accurately to keep a predetermined angle within a plane vertical to the optical axis between the zoom lens groups 21 and 22 formed of two groups and the solid state imaging device 25. Therefore, a solid state imaging apparatus wherein a semiconductor substrate on which are provided respective photosensitive device groups of a solid state imaging device and an optical high-frequency cut off crystal plate arranged in parallel with the above mentioned semiconductor substrate on the incident light path side are integrally fixed so as to be able to be handled as one part is disclosed in the publication of Japanese Patent Application Laid Open No.122087/1984.
Also, a photoelectric transducer device wherein a solid state imaging device itself is made integral by enclosing its sensor part with a resin molding instead of the conventional CCD unit is disclosed, for example, in the publication of Japanese Utility Model Application Laid Open No.170975/1988. This photoelectric transducer device is made by successively laminating a light transmitting conductive film, PIN type amorphous semiconductor layer and conductive film on a light transmitting insulating substrate and is characterized in that the above mentioned light transmitting insulating substrate is a colored glass.
However, in the solid state imaging apparatus wherein a semiconductor substrate on which are provided respective photosensitive device groups of a solid state imaging device and an optical high-frequency cut off crystal plate arranged in parallel with the above mentioned semiconductor substrate on the incident light path side are integrally fixed so as to be able to be handled as one part and which is disclosed in the publication of Japanese Patent Application Laid Open No.122087/1984, it is attempted to dissolve the moire by using the optical high-frequency cut off crystal plate but this crystal plate is expensive. Further, the optical high-frequency cut off crystal plate is only held as mounted on the peripheral edge on a receiving part provided on the semiconductor substrate and is therefore far from one part.
Also, the photoelectric transducer device which is made by successively laminating a light transmitting conductive film, PIN type amorphous semiconductor layer and conductive film on a light transmitting insulating substrate, is characterized in that the above mentioned light transmitting insulating substrate is a colored glass and is disclosed in the above mentioned publication of Japanese Utility Model Application Laid Open No. 170975/1988 is made integral by enclosing the sensor part with a resin molding but has the colored glass which is the light transmitting insulating substrate made separately so that the surface must be ground and is still of a two-body structure.
Now, on the solid state imaging device itself, there is recently established a technique of integrally forming a solid state imaging device including leads by clear molding the chip of the solid state imaging device of a plastic molded transparent resin. The surface of a clear molded package is finely polished to be used as a perfect plane and an optical LPF to remove a moire is separately provided.
For this optical LPF are used not only a crystal plate filter but also a lenticular plate on which are arranged minute cylindrical lenses of a partly arcuate cross-section and a phase filter on which transparent films are formed like stripes by evaporative deposition and which controls a phase filter.
Thus, the solid state imaging device and optical LPF are provided separately from each other and an attempt to combine them into one has never been made.